This invention relates to milling cutters, particularly notched milling cutter blades and a cutter assembly incorporating notched blades.
Notched milling cutter blades are known to be useful for high speed machining operations. Notched blades make smaller chips, reduce pressures and require less horsepower. With such blades, however, it is desirous to use positive axial rake in order to obtain proper chip flow and avoid damage by the chips to the blade, cutter, and workpiece. Negative axial rake tends to undesirably retain chips in the cutter chip slot, to the detriment of the work and cutter. Positive radial rake used in combination with negative axial rake amplifies this detrimental tendency.
Yet, it has been determined that the use of negative axial rake with positive radial rake can effect better cutting action. The problem is to obtain good chip removal while doing this. If negative radial rake is employed, then negative axial rake is normally used to encourage chip discharge as much as possible.
Another difficulty found to exist when attempts are made to use a notched blade at a rake angle is the interference resulting between a lateral wall of each notch and the corresponding rib which remains on the workpiece as the notched cutting edge moves along the workpiece.